Problem: $f(x)=(x+2)(x-4)$ 1) What are the zeros of the function? Write the smaller $x$ first, and the larger $x$ second. $\text{smaller }x=$
$\begin{aligned} (x+2)(x-4)&=0 \\\\ x+2=0&\text{ or }x-4=0 \\\\ x={-2}&\text{ or }x={4} \end{aligned}$ There are many ways to find the vertex. We will do it by using the fact that the $x$ -coordinate of the vertex is exactly between the two zeros. $\begin{aligned} \text{vertex's }x\text{-coordinate}&=\dfrac{({-2})+({4})}{2} \\\\ &={1} \end{aligned}$ Now we can find the vertex's $y$ -coordinate by evaluating $f({1})$ : $\begin{aligned} f({1})&=({1}+2)({1}-4) \\\\ &=(3)(-3) \\\\ &=-9 \end{aligned}$ In conclusion, $\begin{aligned} \text{smaller }x&=-2 \\\\ \text{larger }x&=4 \end{aligned}$ The vertex of the parabola is at $(1,-9)$